Certain difluoramino compounds

ABSTRACT

1. Fluorinated compounds of the group consisting of compounds having the formula WHEREIN N IS A NUMBER OF THE GROUP 0 AND 1 AND R is an atom of the group hydrogen and fluorine, all R&#39;&#39;s being identical in any one compound.

nite States Patent Wright et al.

[ Sept. 5, 1972 [54] CERTAIN DIFLUORAMINO COMPOUNDS ['73] Assignee:Minnesota Mining and Manufacturing Company, St. Paul, Minn.

22 Filed: Nov. 15,1962 21 Appl.No.:239,1 01

[52] US. Cl. ..26(l/583 NI-I, 149/109 [51] Int. Cl. ..C07c 87/20, C07087/22 [58] Field of Search ..26/583, 583 NH [56] References Cited OTHERPUBLICATIONS Hoffman et a1., Chem. Reviews, Vol. 62, pp. 12- 18 (1962)Primary ExaminerLeland A. Sebastian Attorney-Frank A. Steldt and DonaldC. Gipple EXEMPLARY CLAIM l. Fluorinated compounds of the groupconsisting of compounds having the formula LI HRM ln B KE):

wherein n is a number of the group O and l and R IS AN ATOM OF THE GROUPHYDROGEN AND FLUORINE, ALL Rs being identical in any one compound.

6 Claims, No Drawings CERTAIN DIFLUORAMINO COMPOUNDS This inventionrelates to fluorinated oxidants and more particularly to certain newpoly(difluoraminomethyl)-substituted oxidant compounds.

Fluorinated organic compounds containing several difluoramino groups areknown, and some of these are powerful oxidants useful in propellant andexplosive compositions. So far as is known, however, compoundscontaining carbon in which all four valences are substituted byfluorinated nitrogen groups, have not been heretofore known.

It is an object of this invention to produce fluorinated oxidantscontaining only carbon, nitrogen and fluorine, and in which the carbonatoms are attached only to nitrogen.

A further object of theinvention is to provide a process for producingthe said fluorinated oxidant compounds.

Other objects of the invention will be apparent from the disclosureshereinafter made.

The compounds of the invention include tetrakis (difluoramino)methane,having the structural formula NF: and

di tris(difluoramino)methyl fluoramine, having the structural formulaNF; NFz

z- NCNFz z N F2 The compounds of the invention are strongly oxidizingmaterials which are characterized by having relatively low vaporpressures at ordinary temperatures.

'Thus, they can be employed as storable oxidants for propellant systems.They are powerful oxidizing compounds because they contain the maximumpossible number of fluorinated amino groups attached to carbon.

The compounds of the invention are produced by fluorination of novelintermediate adducts represented by the following formula:

wherein R is a member of the group consisting of fluorine and theradical will C-NF2 NFH The intermediate adducts are readily produced bythe action of ammonia or its equivalent on perfluoroguanidine,represented by the formula:

or on perfluorobiguanide having the formula:

The reaction may be illustrated by the following equation:

in which R represents a member of the group consisting of fluorine andthe tris(difluoramino )methyl radical, i.e., the radical of the formula:

R has the significance set forth hereinabove and R is a member of thegroup consisting of fluorine and the radical NFZ (|3=NF Because thecompounds of the invention contain only fluoramino groups and carbon,they are characterized by having an infrared absorption spectrumcontaining a continuous strong absorption band with several peaksbetween 10 and 11 microns, corresponding to the NF bonds, and a lessstrong peak at about 8.9 microns corresponding to the CN bonds. Thecompounds have extremely strong oxidizing power and are shock sensitive.

The intermediate adducts are likewise shock sensitive materials, whichare stable at temperatures of the order of about 0 C. They are viscousoils of low vapor pressure which decompose before they boil. Preferredintermediates are those which are produced by the reaction of ammoniawith perfluoroguanidine and perfluorobiguanide.

The fluorinated compounds from which the intermediate adducts areprepared are produced by direct fluorination of ammeline, to produceperfluoroguanidine, and biguanide, to produce perfluorobiguanide. Thesemethods are described more fully in the copending application for U.S.Letters Pat. of Koshar and Husted, Ser. No. 99,632 filed Mar. 30, 1961now U. S. Pat. No. 3,461,162.

In preparing the adducts, the reaction of the ammonia with thefluorinated compound is carried out at low temperatures of the order ofabout 40 to 20 C. in a solvent such as acetonitrile. The adduct is thenisolated by evaporating the solvent and any low-boiling concomitants atlow temperatures, of the order of about 20 to 0 C. The purified adductis then fluorinated, by treating directly with fluorine at temperaturesin the range of about 50 to +50 C., preferably not above +25 C. Amixture of products is obtained from which the desired end product ofthe invention is recovered, as by gas-liquid chromatography. 5

Because of their extremely strong oxidizing power and their shocksensitivity, it is necessary that the compounds of the invention and theintermediate compounds as well as the starting materials be handled withcaution. Manipulation of the compounds as well as the conduct of thereactions call for extreme care and precautions to prevent injury in theevent of explosion.

The fluorinated oxidant derivatives of the invention are useful inexplosive and propellant compositions. They can be ignited as by meansof a squib or exploded with a cartridge. Propellant compositionscontaining the compounds of the invention, combined with fuel such aslithium or boron and optionally with an additional oxidizer such asammonium perchlorate to consume any carbon present, such as that in anyorganic binder used, burn with intense heat and the formation of largevolumes of gases.

The following examples will more specifically illustrate the process forthe preparation of the compounds of the invention and their properties.

EXAMPLE 1 In a 10 ml. glass reactor equipped with a magnetic stirringbar and a 4 mm. Fisher Porter polytetrafluoroethylene needle valve isplaced 4 ml. of dry acetonitrile which has been distilled fromphosphorous pentoxide. Into this solvent is condensed anhydrous ammonia(0.014 g., 0.81 X 10' mole). The mixture is warmed, thoroughly mixed andcooled to 119" C. with a bromoethane slush bath. Perfluoroguanidine(0.15 g., 1.0 X 10' mole) is introduced by condensation at -ll9 C. Thereactor is closed, stirring is begun and the reactor is allowed to warmslowly in an empty but cold glass dewar flask until the acetonitrilemelts. The mixture is stirred for 1 hour at 20 C. All volatilecomponents are removed from the reactor by reducing the pressure to lessthan 0.1 mm. for one-half hour at C. The residue thereafter remaining inthe flask consists of small amounts of a white solid and of a yellowviscous oil. This oil is dissolved in about 0.2 g. of dry acetonitrileand a fluorine nuclear magnetic resonance spectrum is obtained. The oilis identified as the adduct H NC(NF )CNFH by absorptions at 20.5 (NFgroups) and at +l35.l d (double fivefold, NFl-l group). The .1 valuesfor the peak at +135.l are 50.5 C/S for the doublet and 9.8 C/S for thefivefold splitting.

A small amount of trifluoroguanidine, H NC(NF NF is obtained as aby-product as determined by fluorine nuclear magnetic resonanceabsorptions at 46 (NF group) and at +52 NF group).

The adduct H NC(NF NFH is stored in a closed 60 vessel at 78 C. until itis reacted further.

EXAMPLE 2 The compound H NC(NF NFH (0.080 g.) prepared as described inExample 1, is fluorinated with 6.1 percent fluorine diluted with drynitrogen in the absence of a solvent in a glass reactor at 0 C. forabout 2.5 hours. A total of 0.07 moles of fluorine is passed through thereactor. The product gases are swept through sodium fluoride pellets at25 C. in order to remove hydrogen fluoride and are collected in a dryglass trap which is cooled with liquid oxygen. The trap contains amixture of compounds which include FC(NF and C(NF,).,. These componentsare separated by gas-liquid chromatography on a column consisting of 33percent Kel-F (polychlorotrifluoroethylene) tetramer on Celite(diatomaceous earth) at 25 C. The relative retention times, T relativeto CFCl are: CF(NF 36.2; and C(NF 148. (Relative retention time isdefined as follows:)

T component-T air u T, CFCl3Tr air X These components are collected fromthe chromatography column in dry traps which are cooled with liquidnitrogen.

Tetrakis(difluoramino)methane is a liquid with a boiling point of about35 C. The liquid explodes when hit a sharp blow from a hammer, but isunchanged when stored in the gas phase with water. The infrared spectrumof the tetrakis(difluoramino) methane contains a continuous strongabsorption at 10-11 microns with three peaks at about 10.15, 10.45 and10.9 microns which are due to N-F groups and a weak absorption at about8.9 microns which is due to the C-N group. A nuclear magnetic resonancespectrum containing a single peak at about 30 d) is consistent with thestructure of C( NF EXAMPLE 3 Perfluorobiguanide is treated with ammonia,the resulting adduct is isolated as a viscous oil of the structure andfluorinated as above.

The products of fluorination are subjected to gasliquid chromatography,the fraction of the major components thus fluorinated having the longestretention time being di-[tris(difluoroamino)methyll-fluoramine. Theliquid thus obtained is shock sensitive and strongly oxidizing.Characteristic absorption peaks in its infrared spectrum are severalpeaks in a strong continuous absorption band at 10-11 microns indicatingN-F bonds and a weaker peak at about 8.9 microns owing to the C-N bond.

What is claimed is:

1. Fluorinated compounds of the group consisting of compounds having theformula L U h in M wherein n is a number of the group 0 and l and R isan atom of the group hydrogen and fluorine, all Rs being identical inany one compound.

2. Tetrakis(difluoramino)methane represented by the formula: 1

N F 2 N F N F 2 3. Di[tris(difluoramino)methyllfluoramine represented bythe formula:

4. A compound having the formula:

5. A compound represented by the formula:

wherein R is a member of the group consisting of fluorine and thetris(-difluoramino)methyl radical, which comprises directlyffluorinatinga compound of the formula:

wherein R is a member of the group consisting of fluorine and theradical having the formula:

under substantially anhydrous conditions at a temperature in the rangeof about -50 to +50 C.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIQN Patent No. 3, 9,5i a d ptem er 5, 1972 Inventofls) Charles D. Wright and Joseph La MarZollinger It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 2 line 1 NF C-N-C NF" should read --NF=CN-C=NF-- Column 3, line51, "H2NC(NF2)CNFH" should read -H2NC(-NF2)2NFH- Column 3, line 56,"H2NC(NF2) should read -H2NC(NF2)= Column 3 line 59, NF group)" shouldread -(=NF group)- H;

Signed and sealed this 3rd day of April 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents FORM PO-105O (0-69) USCOMM-DC 60376-P89 fi u,s. GOVERNMENTPRINTING OFFICE was 03B6334 UNITED STATES OFFICE CERTIFICATE OFCORRECTION Patent. 3, 9,5 Dated septembe-rm 97 Inventor(s) Charles D.Wright and Joseph La Mar Zollinger It is certified that error appears inthe above-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 2, line 4, "NF C-N-C NF" should read -NF=C-NC=NF- Column 3, lirie51, "H NC(NF )CNFH" should read --H2NC(-NF2)2NFH- Column 3, line 56, "HNC(NF vshould read --H' NC(NF Column 3, line 59, NF group)" should read(=NF group) Signed and sealed this 3rd day of April 1973.

(SEAL) Attest:

EDWARD M.PLETCHER,JR. I I ROBERT GOTTSCHALK Attesting OfficerCommissioner of Patents FORM 1 0-1050 (10459) USCOMWDC 6O376 p69 fi HTS.GOVERNMENT PRINTING OFFICE I959 O-3E6-334

1. FLUORINATED COMPOUNDS OF THE GROUPS CONSISTING OF COMPOUNDS HAVINGTHE FORMULA
 2. Tetrakis(difluoramino)methane represented by the formula:3. Di( tris(difluoramino)methyl) fluoramine represented by the formula:4. A compound having the formula:
 5. A compound represented by theformula:
 6. A process for the preparation of a compound of the formula:wherein R is a member of the group consisting of fluorine and thetris(difluoramino)methyl radical, which comprises directly fluorinatinga compound of the formula: wherein R1 is a member of the groupconsisting of fluorine and the radical having the formula: undersubstantially anhydrous conditions at a temperature in the range ofabout -50* to +50* C.